Mechanical locking system for floor panels

ABSTRACT

Ceramic and stone tiles are shown, which are provided with a locking system including a separate strip part connected to vertical and horizontal grooves formed in the tile edge. A set of ceramic or stone tiles including a first tile provided with a first edge and a second tile provided with a second edge wherein the tiles are provided with a locking system for locking the first edge to the second edge in a horizontal direction parallel with a tile surface and in a vertical direction perpendicular to the horizontal direction, said locking system includes a first and a second tongue and a strip part provided with a first and a second locking element.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. application Ser. No.14/902,706, filed on 4 Jan. 2016, which is a U.S. national stage ofInternational Application No. PCT/SE2014/050877, filed on Jul. 8, 2014,which claims the benefit of SE 1400291-9, filed on Jun. 10, 2014, andthe benefit of SE 1350856-9, filed on Jul. 9, 2013. The entire contentsof each of U.S. application Ser. No. 14/902,706, InternationalApplication No. PCT/SE2014/050877, SE 1400291-9, and SE 1350856-9 arehereby expressly incorporated by reference herein.

TECHNICAL FIELD

The disclosure generally relates to the field of mechanical lockingsystems for floor panels and building panels. The disclosure showsfloorboards, locking systems and production methods.

FIELD OF APPLICATION OF THE INVENTION

Embodiments of the present invention are particularly suitable for usein indoor and outdoor floors and walls, which are formed of ceramic orstone material and which are intended to be joined with a mechanicallocking system.

The invention may also be used to lock floor panels which are made up ofone or more upper layers of wood or wood veneer, decorative laminate,powder based surfaces or decorative plastic material, an intermediatecore of wood-fibre-based material or plastic material and preferably alower balancing layer on the rear side of the core.

Floor panels of solid wood or with a surface layer of cork, linoleum,rubber or soft wear layers, for instance needle felt glued to a board,printed and preferably also varnished surface and floors with hardsurfaces such as stone, tile and similar materials bonded to a sheetshaped material are included. Embodiments of the invention may also beused for joining building panels in general which preferably contain aboard material for instance wall panels, ceilings, furniture componentsand similar.

The following description of known technique, problems of known systemsand objects and features of the invention will therefore, as anon-restrictive example, be aimed above all at this field of applicationand in particular at ceramic tiles intended to be mechanically joined toeach other vertically and horizontally on all four edges.

Long and short edges are used to simplify the descriptions. The tilesmay also be square.

BACKGROUND OF THE INVENTION

Ceramic tiles are one of the major materials used for flooring and wallcoverings. The raw materials used to form tiles comprise clay minerals,feldspar and chemical additives required for the shaping process. Onecommon method to produce ceramic tiles uses the following productionsteps. The raw materials are milled into powder and mixed.

Sometimes, water is then added and the ingredients are wet milled. Thewater is removed using filter pressing followed by spray drying intopowder form. The resulting powder is then dry pressed under a very highpressure (about 400 bars) to a tile body with a thickness of 3-10 mm.The tile body is further dried to remove remaining moisture and tostabilize the tile body to a solid homogenous material. One or severallayers of glaze, which is a glass like substance, are applied on thetile body by dry or wet methods. The purpose of tile glazing is toprotect the tile. The glaze is available in many different colours anddesigns. Some glazes may create different textures. The tile is afterglazing fired in a furnace or kiln at very high temperatures (1.300°C.). During firing, the glaze particles melt into each other and form awear resistant layer.

New dry methods have been introduced recently and a tile may be formedby scattering, pressing and firing in a continuous production line witha total production time of about one hour. Large tile blanks may beformed that after firing are divided into individual tiles by forexample laser cutting. This new production technology provides improvedstrengths, flexibility and size tolerances.

Roller screens are often used to create a decorative pattern. Thecontact nature of the rotary screen-printing has many disadvantages suchas breakages and long set-up times. Several tile producers havetherefore recently replaced this conventional printing technology withdigital ink jet printing technology that offers several advantagesmainly related to production flexibility and costs

Tiles are generally installed side by side on a surface such as a flooror wall. An adhesive compound is used as a base. After connection to thesub floor or a wall a grout is spread over and between the tiles tofurther bind the tiles and to fill spaces between adjacent tiles.

The major advantage of a tile-based floor is that the tiles are moisterproof and they do not swell and shrink in changed humidity as otherfloors, for example laminate and wood floors.

Tile floors have several disadvantages compared to laminate and woodfloors. One major disadvantage is that conventional tiles havesignificant dimensional variances in length, width and thickness.However, such production variances are decreasing continuously when newand advanced production methods based on dry forming are introduced andcombined with edge trimming. Another major disadvantage is thatinstallation of tiles is labour intensive. Ceramic tiles are verybrittle and they break without significant deformation. They must beinstalled on rather rigid sub floors and the adhesive compound layer maybreak if the sub floor expands and shrinks. Rather costly and moisturestable sub floor must be used such as cement bonded particleboard andsimilar.

Floor elements comprising thin stone material are similar to ceramictiles. They have similar properties and are installed in a similar way.

There is a need for a tile or stone floor and wall system that is simpleto install, that may cover large floor areas without expansion joints,that may be easy to disassemble and that may be installed on more costefficient sub floors that have a higher moisture movement than theceramic tiles.

DEFINITION OF SOME TERMS

In the following text, the visible surface of the installed floor orwall is called “front side”, while the opposite side, facing the subfloor or the wall, is called “rear side”. The edge between the front andrear side is called “joint edge”. By “horizontal plane” is meant aplane, which extends parallel to the outer part of the surface layer.Upper and outer parts of an edge define a “vertical plane” perpendicularto the horizontal plane. By “vertical locking” is meant locking parallelto the vertical plane. By “horizontal locking” is meant locking parallelto the horizontal plane.

By “up” is meant towards the front side, by “down” towards the rearside, by “inwardly” mainly horizontally towards an inner and centre partof the tile and by “outwardly” mainly horizontally away from the centrepart of the tile.

RELATED ART AND PROBLEMS THEREOF

Laminate flooring usually comprise a wood based core, an upperdecorative surface layer of laminate and lower balancing layer. Alaminate surface comprises melamine-impregnated paper. The most commoncore material is fibreboard with high density and good stability usuallycalled HDF—High Density Fibreboard.

Laminate floor panels of this type are installed floating on a sub floorand joined mechanically by means of so-called mechanical lockingsystems. These systems comprise locking means, which lock the panelshorizontally and vertically. The mechanical locking systems are usuallyformed by machining of the core of the panel. Alternatively, parts ofthe locking system may be formed of separate materials, for instancealuminium or HDF, which are integrated with the floor panel, i.e. joinedwith the floor panel in connection with the manufacture thereof.

The main advantages of floating floors with mechanical locking systemsare that they are easy to install. They may also easily be taken upagain and used once more at a different location.

It is known that mechanical joining of long edges as well as short edgesin the vertical and horizontal direction may be made I several ways. Oneof the most used methods is the angle-snap method. The long edges areinstalled by angling. The panel is then displaced in locked positionalong the long side. The short edges are locked by horizontal snapping.The vertical connection is generally a tongue and a groove. During thehorizontal displacement, a strip with a locking element is bent and whenthe edges are in contact, the strip springs back and a locking elemententers a locking groove and locks the panels horizontally. Such a snapconnection is complicated since a hammer and a tapping block has to beused to overcome the friction between the long edges and to bend thestrip during the snapping action.

Similar locking systems may also be produced with a rigid strip and theyare connected with an angling-angling method where both short and longedges are angled into a locked position. Such installation method isdifficult to use if the panels are large and heavy.

Recently advance so called fold down locking systems have beenintroduced that allow a very easy single action installation with anangling action only that locks the long and short edges. A flexibletongue attached to the short edge is used to connect the short edgeswith a scissor like movement when a long edge is locked with angling.

The majority of all mechanical locking systems used in laminate and woodfloorings are formed by rotating diamond tools. Such forming may be madein high speed and with high precision. The locking systems compriseprotruding parts such as a tongue for the vertical locking and a stripfor the horizontal locking.

Protruding parts are difficult and practically impossible to form inceramic material especially in thin ceramic tiles that comprise brittleedges. Spaces between the edges provide additional problems since atongue must extend over a considerable distance from an edge to coverthe space between the edges and to enter into a tongue groove of anadjacent edge.

Diamond tools may be used to form the tile edges. However, theproduction speed is a fraction of the speed that is used to formadvanced joint geometries in wood and plastic based materials. Specialcooling systems, generally based on water-cooling must be used to formtile and stone material.

Several attempts have been made to improve tile installations byattaching ceramic and stone tiles to a separate sheet shaped materialthat may be formed with a mechanical locking system comprisingprotruding parts such that a floating installation similar to laminatefloorings may be obtained.

U.S. Pat. No. 8,156,705 describes a tile having at least one couplingmember that cooperatively engages a coupling member of an adjacent tile,such that adjacent tiles may be reasonably secured to one anotherwithout the use of grout. The tiles are moulded into a synthetic supportstructure that comprises a conventional mechanical locking system.

U.S. Pat. No. 2011/0113713 describes a method for arranging a tile in amould, and injecting a polymer into the mould. The injected materialmechanically anchors the substrate to the tile. A mechanical locking anda surrounding grout gasket may also be formed.

Attaching tiles to a separate sheet material or a mould is expensive.The floor thickness increases and a moisture stable tile is difficult tocombine with wood base sheet material that expands and shrinks whenrelative humidity varies between dry and wet conditions.

It is known that a locking strip may be formed of a separate materialsuch as aluminium or HDF and that such strip may be clamped in undercutgrooves or attached into a horizontally extending groove formed at anedge of a laminate panel by snapping pressing and/or turning. Suchsystems are described in WO 94/26999 and WO 03/083234 (ValingeInnovation AB). It is also known that several strip parts spaced formeach other may be attached to a long side edge in order to obtainfurther cost savings.

WO 2001075247 describes a locking system for joining sheet shapedflooring elements with tight joints. The floor elements are constitutedof solid wood, fibreboard or particleboard. Long edges are locked withconventional locking system comprising a protruding tongue and aprotruding strip. The short edges are joined by vertical displacementand by means of a separate vertical assembly joining profile. The shortedge comprises an edge geometry, which requires that substantial amountsof the edge material are removed. The locking system is not suitable toinstall tiles, which are spaced from each other.

WO 03/083234 describes a locking system that comprises a strip and atongue made of separate material. This system is not suitable to locktiles with edges that are spaced from each other. The geometry of thelocking system is very complicated to produce in ceramic material.

As a summary it may be mentioned that known locking systems are notsuitable to connect ceramic tiles having a brittle tile body since thenecessary strength and flexibility of protruding portions formed inceramic material is not sufficient and the geometry of the edges isdifficult to produce with moulding or machining of ceramic material.

The above description of various known aspects is the applicant'scharacterization of such, and is not an admission that any of the abovedescription is considered as prior art.

SUMMARY OF THE INVENTION

An overall objective of embodiments of the present invention is toprovide an improved and more cost efficient locking system for primarilyfloating installation of ceramic and stone tiles which allows that theedges may be locked to each other mechanically with angling, and/orhorizontal snapping and/or vertical snapping.

A specific objective is to form a locking system that comprises a verysimple joint geometry and minimum amount of separate material attachedto a tile and that may be formed with smallest possible machining of thetile edges, preferably without any brittle protruding parts.

Other specific objectives are to provide tiles with an integrated groutmaterial, improved décor properties, to eliminate size tolerances and toprovide panels comprising combination of ceramic material and otherlighter and more cost efficient materials.

The above objects of embodiments of the invention may be achieved whollyor partly by locking systems and tiles formed according to thedisclosure. Embodiments of the invention are evident from thedescription and drawings.

The invention is based on the insight that vertical and horizontalgrooves with a specific geometry may be formed with high precision inedge portions of a thin ceramic or stone tile body and that such groovesmay be used as a part of a locking system allowing a mechanical locking.

The invention is also based on a second understanding that separatestrip shaped material comprising vertically protruding locking elementsand horizontally protruding tongues may be mechanically connected tosuch groves and that such separate strip shaped materials and groovesmay be used to accomplish a strong, cost efficient and simple floatinginstallation of ceramic or stone tiles on a floor or on a wall in indooror outdoor applications.

The invention is based on a third understanding that the grooves andseparate strip shaped material may be formed such that it is possible toovercome the size tolerances off ceramic tiles that generally areinstalled with a space between the edges and that machining of the upperedges to a pre-determined perfect size may be avoided.

The invention is based on a fourth understanding that pre formed tilescomprising vertical and horizontal grooves may be produced and that suchpre formed tiles may reduce the final machining of the edges which isneeded to form the required geometry.

Thin ceramic surfaces may also be bonded to materials that are moisturestable and the ceramic surface may be used to form a part of the lockingsystem.

A first aspect of the invention is a set of ceramic or stone tilescomprising a first tile provided with a first edge and a second tileprovided with a second edge. The tiles are provided with a lockingsystem for locking the first edge to the second edge in a horizontaldirection parallel with a tile surface and in a vertical directionperpendicular to the horizontal direction. The locking system comprisesa first and a second tongue and a strip part provided with a first and asecond locking element. The first edge is provided with a firsthorizontal groove and a first vertical groove formed in a body of thefirst tile. The first locking element is configured to cooperate withthe first vertical groove for locking in the horizontal direction andthe first tongue is configured to cooperate with the first horizontalgroove for locking in the vertical direction. The second edge isprovided with a second horizontal groove and a second vertical grooveformed in a body of the second tile. The second locking element isconfigured to cooperate with the second vertical groove for locking inthe horizontal direction and the second tongue is configured tocooperate with the second horizontal groove for locking in the verticaldirection. Each of the first and the second horizontal groove comprisesan upper lip and a lower lip. The lower lip of the first horizontalgroove extends horizontally to or is within an upper and outer part ofthe first edge and the lower lip of the second horizontal groove extendshorizontally to or is within an upper and outer part of the second edge.There is a space between the outer and upper part of the first edge andthe outer and upper part of the second edge in a locked position of thefirst and the second edge.

The lower lip of the first horizontal groove may extend horizontallyessentially to the upper and outer part of the first edge and the lowerlip of the second horizontal groove may extends horizontally essentiallyto the upper and outer part of the second edge.

The depth of one of the horizontal grooves of the first or the secondtile, measured as the horizontal distance from a vertical plane, locatedat the upper and outer part of the edge, and to the groove bottom, mayvary along the same edge of one of the tiles or between the same edgesof two different tiles.

The depth of the horizontal groove may vary with at least 0.10 mm.

The strip part may comprise a vertically extending tongue body and afirst tongue protruding from the vertically extending tongue body.

The locking system may be configured to be locked by angling and/orvertical snapping and or horizontal snapping of the first and the secondtile.

A second aspect of the invention is a set of ceramic or stone tiles,each comprising a first and a second edge which are provided with alocking system for locking in a horizontal direction parallel with atile surface and in a vertical direction perpendicular to the horizontaldirection. The first edge of the first tile is lockable to the secondedge of the second tile. The second edge of the first tile is lockableto the first edge of the second tile in a horizontal direction parallelwith a tile surface and in a vertical direction perpendicular to thehorizontal direction, wherein said locking system comprises a first anda second tongue and a strip part provided with a first and a secondlocking element. The first edge is provided with a first horizontalgroove and a first vertical groove formed in a body of the first and thesecond tile. The second edge is provided with a second horizontal grooveand a second a vertical groove formed in a body of the first and thesecond tile. The first locking element is configured to cooperate withthe first vertical groove for locking in the horizontal direction andthe first tongue is configured to cooperate with the first horizontalgroove for locking in the vertical direction. The second locking elementis configured to cooperate with the second vertical groove for lockingin the horizontal direction and the second tongue is configured tocooperate with the second horizontal groove for locking in the verticaldirection. Each of the first and the second vertical groove comprises afirst groove wall, a second groove wall and an upper surface. The firstgroove wall of the first vertical groove is closer to the outer part ofthe first edge than the second groove wall of the first vertical groove.The first groove wall of the second vertical groove is closer to anupper and outer part of the second edge than the second groove wall ofthe second vertical groove. There is a first a horizontal distancebetween the first groove wall of the first edge of the first tile and anupper and outer part of the first edge of the first tile. There is asecond horizontal distance between the first groove wall of the secondedge of the first tile and an upper and outer part of the second edge ofthe first tile. There is a third horizontal distance between the firstgroove wall of the first edge of the second tile and an upper and outerpart of the first edge of the second tile. There is a fourth horizontaldistance between the first groove wall of the second edge of the secondtile and an upper and outer part of the second edge of the second tile.The first horizontal distance varies along the first edge of the firsttile, and/or the second horizontal distance varies along the second edgeof the second tile, and/or the third horizontal distance varies alongthe first edge of the second tile, and/or the fourth horizontal distancevaries along the second edge of the second tile, and/or the firsthorizontal distance is different from third horizontal distance and/orthe second horizontal distance is different from the fourth horizontaldistance.

In a locked position of the first and the second edge there may be aspace between the upper outer parts of the first and second edge.

Each of the first and the second horizontal groove may comprise an upperlip and a lower lip. The lower lip of the first horizontal groove mayextend horizontally to or is within an upper and outer part of the firstedge and the lower lip of the second horizontal groove may extendshorizontally to or is within an upper and outer part of the second edge.

The strip part may comprise a vertically extending tongue body with afirst tongue that protrudes from the vertically extending tongue body.

The locking system may be configured to be locked by angling and/orvertical snapping of the first and the second tile.

A third aspect of the invention is a ceramic tile provided with anembossed surface and a décor. The embossing is in register with thedécor. The embossing comprises upper and lower surface portion. An uppersurface portion comprises a different gloss level than a lower surfaceportion.

The décor may be a wood design and the different gloss levels may beformed by a digitally applied powder.

A fourth aspect of the invention is a set of floor panels comprising afirst and a second panel comprising a ceramic surface layer and a corecomprising thermoplastic material mixed with wood or mineral fillers. Amechanical locking system is formed in the core of the first and thesecond panel. The mechanical locking system comprises a strip providedwith a locking element at a first edge of the first panel and a lockinggroove at a second edge of the second panel. The locking element and thelocking groove are configured to cooperate for locking of the first andthe second edge in a horizontal direction parallel with the ceramicsurface layer. The mechanical locking system comprises a tongue at thesecond edge and a tongue groove formed in the first edge. The tongue andthe tongue groove are configured to cooperate for locking of the firstand the second edge in a vertical direction perpendicular to thehorizontal direction. The thickness of the ceramic surface layer is inthe range of 2 mm to 5 mm. The tongue groove comprises an upper lip thatis essentially formed by the ceramic surface layer.

In a locked position of the first and the second edge there may be aspace of about 1-10 mm between the ceramic surface layers.

A fifth aspect of the invention is a pre formed ceramic tile intended tobe provided with a locking system. A groove is formed at the rear sideof a tile edge.

A first thickness of an outer edge of the pre formed ceramic tile may belower than a second average thickness of the tile body of the pre formedceramic tile.

The thickness difference between the first thickness and the secondaverage thickness may be about 1-3 mm.

The groove may be an equalizing groove comprising an upper surface thatis essentially parallel with an upper surface of the pre formed ceramictile. The upper surface may extend from the outer part of the edge andinwardly.

The upper surface of the equalizing groove may extend over a horizontaldistance of about 3-20 mm.

The rear side of the pre formed ceramic tile edge may comprises avertical groove spaced from the outer edge and an equalizing grooveextending from the vertical groove and to the outer part of the edge.

A sixth aspect of the invention is a set comprising a first tile, asecond tile and a strip part, which preferably comprises a polymer ormetal material, wherein said first and second tile are ceramic or stonetiles. A first edge of the first tile or a second edge of the secondtile comprises a vertical groove and a horizontal groove formed in abody of the first or the second tile respectively. The strip part isconfigured to be connected to one of the vertical grooves and one of thehorizontal grooves, formed on the same edge, for vertical lockingperpendicular to the tile surface and horizontal locking parallel to thetile surface of the first and the second tiles. In locked position thereis a space between upper parts of the first and second edge.

Vertical and horizontal grooves may be formed in the first edge of thefirst tile and the second edge of the second tile. The strip part may beconfigured to be connected to the horizontal and vertical groves formedin the first edge of the first tile and in the second edge of the secondtile.

The horizontal groove of the first edge or the second edge may comprisean upper lip and a lower lip. The lower lip may extend horizontally toor is within an upper and outer part of the respective first or secondedge.

The strip part may comprise a tongue having a vertically extendingtongue body located in the space.

The tiles may be connected with vertical or horizontal snapping whereinthe tongue body is displaced horizontally in the space during locking.

The major advantages of the invention are that a locking system may beformed with a very limited machining of the tile edges and no protrudingparts formed in the tile body are needed to accomplish a mechanicallocking. The locking system is formed with a geometry that is adapted tothe production methods of the tiles and to the possibility to pre formtiles comprising grooves that may be used as a part of the final jointgeometry. This will reduce the material that must be removed during thefinal forming of the edges. The locking system is adapted to positionand align tiles with normal size tolerances and generally no machiningof the upper parts of the edges is needed. The strip part comprises asimple geometry that may be formed in a cost efficient way by punchingor extrusion of a plastic or metal material. The strip part is alsoformed such that it is easy to factory connect to a tile edge prior toinstallation or by the installer during installation.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosure will in the following be described in connection toexemplary embodiments and in greater detail with reference to theappended exemplary drawings, wherein:

FIGS. 1a-d illustrate locking systems according to known technology.

FIGS. 2a-d illustrate displaceable tongues and separate strip partsaccording to known technology.

FIGS. 3a-3b illustrate floorboards with locking systems according toknown technology.

FIGS. 4a-e illustrate a locking system according to an embodiment of theinvention.

FIGS. 5a-f illustrate a method to fix the strip part to an edgeaccording to an embodiment of the invention and locking with angling andsnapping.

FIGS. 6a-e illustrate alternative embodiments of the invention.

FIGS. 7a-d illustrate embodiments of strip parts.

FIG. 8 illustrates an embodiment of a tile with four strip parts.

FIGS. 9a -d 6 illustrate embodiments of a sub floor panel with edgescomprising a mechanical locking system, a tile connected mechanically toa panel and forming of edge portions

FIGS. 10a-10e illustrate embodiments of pre formed tiles.

FIGS. 11a-11d illustrate an alternative embodiment of the invention

FIGS. 12a-12e illustrate an alternative embodiment of the invention

FIGS. 13a-13d illustrate embodiments of an installation of tiles, anembossed tile surface and underlay material connected to a tile

FIGS. 14a-14e illustrate embodiments of locking systems suitable to lockshort edges

FIGS. 15a-15e illustrate embodiments of flexible tongues

FIGS. 16a-16e illustrate an alternative embodiment of the invention anda method to connect a strip part

FIGS. 17a-17e illustrate an alternative embodiment of the invention andtiles installed on a wall.

FIGS. 18a-18d illustrate an alternative embodiment of the invention anda method to disassemble installed tiles

FIGS. 19a-19d illustrate embodiments of locking system with a resilientsnap tab

FIGS. 20a-20d illustrate an embodiment of a locking system comprising anintegrated grout material

FIGS. 21a-21e illustrate an embodiment of a method to eliminate sizetolerances.

FIGS. 22a-22b illustrate an embodiment of an application of a groutmaterial.

FIGS. 23a-23d illustrate embodiments of application of a grout materialand an installation with horizontal snapping.

FIGS. 24a-24b illustrate an embodiment of an installation withhorizontal snapping of two perpendicular edges.

FIGS. 25a-25b illustrate an embodiment of a strip part that may be usedto connect corner sections.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

To facilitate understanding, several locking systems in the figures areshown schematically. It should be emphasized that improved or differentfunctions may be achieved using combinations of the embodiments.

All embodiments may be used separately or in combinations. Angles,dimensions, rounded parts, spaces between surfaces etc. are onlyexamples and may be adjusted within the basic principles of theinvention.

FIGS. 1a and 1b show a known locking system used in laminate and woodfloors that are locked with angling. The horizontal locking is obtainedby a locking strip 6 with a locking element 8 formed at one panel edge 1that locks into a locking groove 14 formed in another adjacent paneledge 1′. The forming of the strip 6 creates a waste Ws as shown infigure 1b when considerable amounts of material are removed. The lockingsystem comprises protruding parts such as a tongue 10 and a strip 6 thatare formed by machining of the panel edge.

FIG. 1c shows a known locking system used in laminate floors comprisinga separate aluminium strip 6 attached to a lower part of a panel edge. Apart of the strip 6 is bent around an inwardly inclined verticallyextending surface. Such connection of the strip 6 to the panel edge ismade in a separate operation than the machining of the edge. The stripcomprises three different cross section A-A, B-B and C-C that are usedto connect the strip to the panel edge and to lock the panelshorizontally. The length L of the strip is the same along the width W.The part of the strip that extends from the edge comprises a smallcavity 23, which is formed when a part of the strip body is punched andbent around a panel edge. A protruding tongue made in one piece with thecore is used for the vertical connection.

FIG. 1d shows a strip 6, which is attached with snapping into ahorizontally extending groove. This strip is formed by machining and hasthe same cross section along its length. An advanced edge profile isrequired to fix the strip to the edge. The locking system may alsocomprise a separate flexible tongue. Such locking systems suffer fromseveral disadvantages. The material content is high due to the designand only limited material savings may be reached. The fixing of thestrip to the edge is rather complicated and slow. FIG. 2a-2b show alocking system with a separate flexible displaceable tongue 10 ainserted in a horizontally extending displacement groove 9 a formed onthe short edge of a panel. The separate tongue is inserted in high speedand is mainly used to obtain higher flexibility when the panels arelocked with a vertical snapping. The locking system may be used toconnect tiles. The locking system is difficult to produce in thinceramic tile material since the protruding strip 6 may break.

FIGS. 2c and 2d shows locking systems comprising a separate plasticstrip part 6 that may be connected to a tile edge. This locking systemis also difficult to produce in ceramic and stone material since a lotof material must be removed by rotating tools. The protruding tongue 10is brittle and may crack.

FIG. 3a shows a known conventional panel with a strip 6 that extendsalong the whole long edge. Material savings may be increased if severalstrip parts 6 are connected on a long side of a panel as shown in FIG. 3b.

One of the basic principles of the invention is the understanding thatsimple grooves may be formed in the tile body and that such grooves maybe used to connect separate materials comprising protruding parts and toform locking system allowing a strong mechanical locking in a floatingmanner.

FIGS. 4a-4d show a locking system according to one embodiment of theinvention that may be connected with angling, vertical snapping andhorizontal snapping. The locking system may also be unlocked withangling and sliding along the edge. FIGS. 4a, 4b and 4c are side viewsand FIGS. 4d and 4e are top views.

FIG. 4a shows two adjacent edges 1, 1′ of a first 1 a and a second 1 btile. Each tile 1 a, 1 b comprises a first horizontal groove 9 a formedin the first edge 1, a second horizontal groove 9 b formed in the secondedge 1′, a first vertical groove 14 a formed in the first edge 1 and asecond vertical groove 14 b formed in the second edge 1′ and a strippart 6 connected mechanically to the first horizontal 9 a and vertical14 a grooves.

The horizontal grooves 9 a, 9 b are formed in the outer vertical portionof tile edge. FIG. 4b show that the horizontal grooves 9 a, 9 b comprisea horizontal grove opening 17 at a vertical plane VP located at theupper and outer part of the tile edge, an upper lip 12 a lower lip 11,an upper groove wall 18 a lower groove wall 19 and a groove bottom 20.The vertically grooves 14 a, 14 b are formed at the rear side of thetile and are spaced from the outer edges. The vertical grooves 14 a, 14b comprise a vertical groove opening pointing 23 downwards, with a first24 and a second 25 groove wall and an inner groove wall 25 located atthe upper part of the vertical grooves 14 a, 14 b. The first 24 groovewall is located closer to the vertical plane VP than the second groovewall 25.

The strip part 6 is according to the invention preferably used to lockthe edges 1,1′ horizontally inwardly and outwardly and verticallyupwards and downwards. The upper edges are preferably connected to eachother with a pre-determined horizontal space S. This is a majordifference compared to conventional technology where the upper edges arelocked in contact with each other and the strip part 6 is only used topreventing horizontal separation. The space S may be used to form aspecific locking system with a favorable geometry and function asdescribed below. Angling and snapping properties may be improved and thelocking system may be formed with a more cost efficient geometry.

The locking system comprises a strip part 6 having a strip body 7 andupwardly extending first 8 a and a second 8 b locking element atopposite and outer part of the strip body 7. An upper part of the secondlocking element 8 b comprises preferably an upper guiding surface 22that is used to guide the locking element 8 b into the second verticalgroove 14 b during angling, horizontal snapping and vertical locking.

The strip body 7 comprises a first 10 a and a second 10 b upwardlyextending flexible tongue. The tongues 10 a, 10 b have preferably avertically extending flexible tongue body 30, an upper sliding surface31 that may be flexible and a tongue locking surface 32.

The tongue body 30 is preferably at least partly located in the space Sformed by the adjacent edges. Such a locking system provides theadvantage that no material has to be removed from the edge in order toaccommodate a vertically extending tongue body 30. The space S may alsobe used to allow the tongue body 30 to be displaced horizontally in thespace S during vertical and/or horizontal snapping.

The strip part 6 is configured to be locked to the first edge 1 by thefirst tongue 10 a that is inserted into the first horizontal groove 9 aand by the first locking element 8 a that is inserted into the firstvertical groove 14 a. The strip body 7 comprises preferably a fixingelement 16 at an outer part that may be used in some embodiments toobtain a firm connection of the strip part 6 to the tile. The fixingelement may be flexible and may lock against the second groove wall 25.

The locking elements 8 a, 8 b cooperate with the vertical grooves 14 a,14 b and locks the edges 1, 1′ in a horizontal direction and preventshorizontal separation. The flexible tongues 10 a, 10 b cooperate withthe horizontal grooves 9 a, 9 b and locks the edges 1, 1′ vertically andprevents horizontal displacement of the panel edges towards each other.Other parts formed on the strip body may be used to prevent suchhorizontal displacement of the panels towards each other.

Tile and stone material may be formed by rotating hard metal or diamondtools. Even stationary carving, scraping or grinding tools may be used.

Test production shows that small grooves may be formed in a costefficient way with rotating diamond tools and that such grooves may havesufficient strength even in brittle materials such as ceramic or stonematerial if the material content adjacent to the groove is sufficient inrelation to the groove width and depth. A joint geometry with highstrengths may be obtained if the edge preferably only comprises verysmall parts or even more preferably no parts that extend horizontallybeyond the upper edge.

The locking system according to the invention has preferably noprotruding parts such as a tongue or a strip that are formed in the tilebody and that protrudes beyond the upper edge.

Rather small grooves that extend inwardly for example 0.5-2 mm into anedge or at a rear side may be formed and such grooves may havesufficient strength even in thin and brittle ceramic and stonematerials. Preferably there are no or only very small protruding partsextending beyond the upper edge, especially if such protruding parts areformed by machining of the tile edges.

A strong edge groove with for example 2 mm debt may be formed in highspeed with five rotating tools where each tool removes about 0.4 mm ofmaterial. The forming may be made when a tile is displaced in relationto rotating tools. The tile may also be connected to a stationary holderand the tools are displaced in one or several machining steps inrelation to the tile edge.

It is an advantage if no material or very small amounts of material areremoved at the upper part of the edges, especially if such edges areformed with bevels or rounded parts. Tiles are general not completelysquare or rectangular and one edge may have a different length thananother edge. Two edges that meet each other may not be completelyperpendicular.

Such production tolerances are generally eliminated by the spacesbetween the edges that are filled with grout material. It is a majoradvantage if the locking system is formed and configured such that thetiles are installed and aligned with a pre-determined average distancebetween the edges and that the distance deviations are minimized.Preferably the horizontal grooves are formed more precisely than theupper edges. This means that the depth of one or several horizontalgrooves, measured as the horizontal distance from a vertical planelocated at the upper and outer part of a tile edge and to the innersurface a horizontal groove, may vary along the edge. The groove depthof a horizontal groove may be at least 0.10 mm or even 0.20 mm larger atone part of the edge than at another part of the same edge. Thehorizontal groove at all four edges of a tile may be formed with smallertolerances the upper edges. For example a set of tiles according to theinvention may have long edges of 40.0+−0.2 mm and short edges of30.0+−0.2 mm measured at the upper parts of the tile. The distancebetween the inner surfaces of the horizontal grooves may be 36.0+−0.10mm and 26.0+−0.10 mm when 2 mm deep grooves are formed in the edge.

The locking system according to the invention will align all tilesautomatically in a pre-determined position vertically and horizontally.This allows that the space S between the tiles may be decreased comparedto conventional installation. A space S of 2-3 mm may be sufficient andsuch a small space may be used to decrease the amount of grout material.

The grooves are preferably formed in the tile body with rotating diamondtools in a separate production step after the production of the tile.The grooves may also be formed in two steps. The first step may be arough forming that is formed during the tile production. The second stepis the final forming with diamond tools. This two-step forming may beused to reduce the amount of material that must be removed in order toobtain a joint geometry that is needed for a high quality locking systemthat guides the tiles into a correct position vertically andhorizontally during installation.

New and advanced production methods to produce tiles are underdevelopment and such methods will make it possible to produce grooveswith sufficient accuracy in line with the tile production. No furthermachining or forming may be needed to form a locking system.

The strip part 6 may be formed from metal material, preferably fromsteel or aluminium. The strip part 6 is in this embodiment formed bypunching and pressing.

FIG. 4d shows that the flexible tongues may 10 a, 10 b may be spacedfrom each other in the length direction of the tile edge. The material,which is needed to form a tongue 10, is obtained from the strip body. Acavity 59 is formed when the tongue is formed by punching a metal sheet.A cavity is in this embodiment formed between the first tongue 10 a andthe second locking element 8 b.

FIGS. 5a -5e show a method to fix a strip part 6, as described in FIGS.4a -4 e, to an edge of a tile or stone material. The strip may be angledand snapped into the edge from the rear side as shown in FIG. 5a wherebythe flexible tongue 10 a is bended and/or compressed. Alternatively thestrip may be inserted along the edge from one of the tile corners or thetongue 10 a may be inserted in the groove 9 a and the locking element 8a may be pressed into the vertical groove 14 a as shown in FIG. 16 d.

FIG. 5b shows a connection with angling of the second edge 1′ againstthe first edge 1. The first edge 1 may also be angled against the secondedge 1′ with the strip body 7 inserted under the second edge prior toangling. FIG. 5c shows vertical snapping and FIG. 5d horizontalsnapping. FIG. 5e shows two connected edges with a space S between upperedges and FIG. 5f shows a grout material 13 applied in the space S thatmay be a flexible polyurethane material.

FIG. 5b shows that the angling may take place around a rotation point Rpthat is located at the tongue locking surface 32 below the upper part ofthe tongue. This allows that a locking element 8 may be formed with ahigh locking angle and may be combined with a locking distance LD,defined as the horizontal distance from the vertical plane and to thelocking element, which may be 1-1.5 times the tile thickness T or evensmaller for example 0.5-1.0 times the tile thickness T. The advantage isthat a strong locking system may be formed with a compact strip part andless material will be needed to form the locking system.

A tile 1 a with an edge 1 comprising a strip part 6 that is attachedprior to installation, as shown in FIG. 5c , is referred to as a “striptile” A tile 1 b with an edge that is connected to the strip tile 1 awith vertical folding or vertical displacement is referred to as a “fold tile”

A flexible tongue that may be used to connect the edges with a verticaldisplacement may have flexible protrusions in its inner or outer parts.The flexible tongue may also comprise a snap tab at its outer end. Allseparate flexible tongues described in this disclosure may be connectedto the strip tile 1 a or to the fold tile 1 b.

The strip part 6 is preferably connected to the edge mechanically. Gluemay also be used and may be combined with a mechanical connection.

The strip part 6 may be a plastic or metal section. Flexible or rigidtongues may be formed as punched, extruded or injection moulded plasticor metal components.

The strip part may comprise vertically protruding blocking elements thatprevents a horizontal displacement of the edges towards each other.

FIG. 6a shows that the horizontal groove 9 may comprise a lower lip 11that extends horizontally beyond the upper edge and the vertical planeVP or that is locate inwardly spaced from the vertical plane VP with ahorizontal distance to the upper edge as shown in FIG. 6b . Preferablythe lip distance Ld, defined as the horizontal distance from the outerpart of the lower lip 11 and to the vertical plane VP, is less than 0.5times the space S between two adjacent tile edges when a lower lipextends beyond the vertical plane VP as shown in FIG. 6a . The lipdistance is preferably less than the space S between upper adjacentedges when the lower lip 11 is displaced inwardly in relation to thevertical plane VP as shown in FIG. 6b . Such locking systems may beformed in a cost efficient way and limited amounts of materials have tobe removed.

FIG. 6c shows that the edge may also comprise an equalizing groove 21that reduces the average thickness of a tile T1 to a smaller thicknessT2 at an edge portion and allows that a strip part with a thick stripbody may be connected to a tile edge. The equalizing groove may also beused to reduce thickness tolerance between adjacent tile edges.

FIG. 6d shows that a part of the tongue 6 b may be bended away from theedge 1′ and partly displaced into an adjacent horizontal groove 9 aduring vertical folding.

The strip body may be made of about 0.3-0.6 mm thick metal sheetmaterial preferably a stainless steel material. A more preferredthickness is about 0.3-0.4 mm.

FIG. 6e shows that the thickness of the metal strip part may be suchthat an underlay 2 such as a foam may be used to overbridge thethickness of the strip body 7 when the tiles are installed on a subfloor 3.

A flexible grout material 13 may be factory connected to two edges thatmeet each other in a corner section of the tile.

The sub floor 3 may comprise panels with a mechanical locking system onlong and short edges.

FIGS. 7a-7d show embodiments of the strip part 6 that may be a metalpart (FIG. 7a ), an extruded metal or plastic section (FIG. 7b ) or anextruded and machined plastic or metal section (FIG. 7c ) where partshave been removed in order to provide increased flexibility of theflexible tongues 10 a, 10 b. The strip parts 6 may also be formed byinjection moulding. A locking with a vertical displacement may be madewith less resistance if the flexible tongue 10 a may be bended anddisplaced horizontally for example 1-2 mm during locking. FIG. 7d showsa flexible tongue 10 b comprising a flexible tongue body 30 and aflexible sliding surface 31. The flexible tongue 10 b is bended and thesliding surface 31 is bended and compressed inwardly during locking.

The edges may be formed such that a part of the tongue 10 b may bedisplaced into one of the horizontal grooves 9 a and then towards itslocked position into the other adjacent groove 9 b as shown in FIG. 6 d.

FIGS. 8 shows a tile 1 a with 4 strip parts 6 connected to two edges 4b, 4 d. The strip parts may be attached by snapping or insertion alongthe edge.

The strip parts may be factory connected to the tile edge or supplied asindividual component that is attached to a tile edge prior toinstallation. Strip parts 6 may be formed and adapted to a space Sbetween the edges that may vary from 0-10 mm and this may be used tocreate different grout widths. The vertical 14 and horizontal grooves 9may extend from along the whole edge 1 or they may only be formed in apart of the edge 1.

Several strip parts may be connected to an edge. The strip parts mayhave different geometries on different edges or on the same edge. Theedge may also comprise one strip part that extends along essentially thewhole edge.

It is obvious from the drawings that a first edge 1 of a first tile 1 amay be connected to a second edge 1′ of a second tile 1 b and that asecond edge of a first tile 1 a may be connected to a first edge of asecond tile 1 b.

FIG. 9a shows that a strip part 6 may be connected to a panel that maybe used as a sub floor 3. The connection may be made mechanically,preferably by bending some parts of the strip body 7 into grooves formedin the sub floor panel. FIG. 9b shows that one or several tiles 1 a, 1 bmay be mechanically connected to the sub floor pane 3 that may comprisea conventional mechanical locking system, for example a locking systemshown in figures 1a and 2 a. One or several tiles may be installedmechanically by connecting the sub floor panels 3 to each other.

The advantage is that the tiles are mechanically connected to the subfloor panel without glue. The mechanical connection and the flexibletongues allow that the moisture stable tiles 1, 1′ and a moisturesensitive sub floor 3 may move independently relative each other whenthe relative humidity changes from dry to wet conditions. This makes itpossible to use sub floors comprising for example wood based materialssuch as HDF and particleboard that expand and shrink when relativehumidity is changing.

All embodiments of the invention may be used to connect tiles forforming a floating floor or to connect tiles in vertical application ona wall. The strip part may be nailed to a vertical sheet materialforming a part of a wall system.

Ceramic tiles produced with dry pressing of powder under high pressuremay be formed with a thickness of about 2-5 mm and with high flexibilityand strength.

FIG. 9c shows that such thin tiles may be used as a ceramic surfacelayer 27 in floor panels 1 a, 1 b comprising a moisture stable corematerial 28 such as for example mineral or fibre-cement board or a boardcomprising a mix of thermoplastic material, for example PVC, PE or PPand mineral fillers, similar to so called LVT material, or suchthermoplastic material and wood fibre fillers similar to so called WPCmaterial. Preferably fillers constitute about at least 50% of the weightof a core comprising thermoplastic material.

Ceramic material 27 with a preferred thickness Ta of about 2-5 mm, or2-4 mm or 2-3 mm may be bonded to such moisture stable core material 28.Preferably the thickness Tb of the core is about 3-5 mm or 3-4 mm. A twolayer material with a total thickness Tc of for example 5-10 mm may beformed. Preferably the thickness Tb of the core 28 is larger than thethickness Ta of the ceramic surface layer 27.

A locking system comprising a tongue 10 and a tongue groove 9 forvertical locking and a strip 7 with a locking element 8 that cooperateswith a locking groove 14 formed in an adjacent edge for horizontallocking may be formed in the core material 28. Preferably the upper lip12 of the tongue groove 9 comprises essentially ceramic material thatprovides the strength and prevents vertical displacement of the tongue10. Preferably at least 60% or at least 80% of the thickness of theupper lip 12 comprises ceramic material. Preferably the upper edges arespaced from each other with a pre-determined space S that is formed whenthe locking element 8 enters into the locking groove 14 duringinstallation. Cooperating surface of the locking element 8 and thelocking groove 14 may be used to prevent separation of the panel edgesaway from each other and displacement of the panel edge towards eachother. Cooperating surfaces of the tongue 10 and the tongue groove 9 mayalso be used to create a pre-determined space S and to preventdisplacement of the panel edges towards each other.

FIG. 9d show that the horizontal groove 9 may be formed by ahorizontally rotating tool 41 and that the vertical groove 14 may beformed by a vertically rotating tool 40.

FIGS. 10a -10e show that pre formed tiles 1 a may be produced comprisinga part of the locking system. The pre forming is made preferably priorto the production step when the tile is fired in a furnace or kiln.Grooves may be formed in a very cost efficient way during pressing ofthe powder material and after the pressing step when the tile body isstill soft and very easy to form by for example rotating tools. Groovesmay extend along the whole edge or along a part of an edge and they maybe formed on one edge or on several edges, preferably on one pair ofopposite edges. FIG. 10a shows a pre formed tile edge 1 comprising avertical groove 14. The horizontal distance D1 from the vertical planeVP and to a first groove wall 24 is preferably about 3-20 mm or evenmore preferably 5-15 mm. The final shape may be formed by for examplerotating tools that form a tile edge 1″ comprising a vertical 14 andhorizontal 9 groove adapted to the shape of the strip part and thedefined geometry of a specific locking system. FIG. 10b shows a preformed tile 1 comprising an edge with a thickness T′ that is smaller,preferably about 1-3 mm smaller, than the average thickness T of thetile body. The edge comprises an equalizing groove 21 with an uppersurface 21 a that is essentially parallel with the upper surface of thetile and that preferably extends from the vertical plane VP and inwardlyover a horizontal distance D1 of preferably 5-25 mm. FIG. 10c shows apre formed tile comprising a vertical 14 groove and an equalizing groove21 and FIG. 10d shows a pre formed tile comprising a vertical groove 14,an equalizing groove 21 and a horizontal groove 9. FIG. 10e shows that aprotruding lower lip may be pre formed and may be used to connect astrip part. Pre forming may be used to reduce the material content thatmust be removed to form the edge geometry. The advantage is increasedproduction speed and less tool wear.

FIG. 11a shows a second embodiment of the invention. The flexible tonguecomprises a vertically extending tile body 30 with a tongue lockingsurface 32 and an upper part formed as sliding surface 31 above thelocking surface 32.

FIG. 11b shows that the outer part of the tongue locking surface may beused as a sliding surface 31 that during vertical displacementcooperates with a tile sliding surface 33 formed at the outer and lowerpart of the tile edge. The sliding surface 31 of the tongue may berather small due to the fact that ceramic material is hard and allowssliding against rather small and sharp surfaces. The locking system mayalso be locked with angling and horizontal snapping.

The lower wall 19 of the horizontal groove 9 a is located at a firstupper horizontal plane H1 that is closer to the tile surface than asecond and lower horizontal plane H2 that intersects the upper surface26 of the vertical groove 14 a. The vertical distance between the firstH1 and the second H2 horizontal plane is preferably at least 0.1 timesthe tile thickness T. The horizontal distance D1 between the verticalplane VP and the first groove wall 24 of the vertical groove 14 ispreferably about the same as the tile thickness T or larger.

This embodiment offers the advantage that a strong edge portion may beformed in tile material and that the strip part 6 may be formed in amore cost efficient way with a simple punching operation as shown inFIG. 11 c.

FIG. 11a shows a flexible gout material 13 formed as a flexible stripthat is inserted after installation between the upper edges. FIG. 11dshows a flexible material that prior to installation of a second tile islocated between the edges, preferably at least partly in the horizontalgrooves 9 a, 9 b and that may be used as an edge sealing 15. Such edgesealing 15 may be used when the tiles are installed with a small space Sthat may be a small as for example less than 1.0 mm

FIG. 12a-12d shows another embodiment of the invention. Tiles aregenerally produced with considerable thickness tolerances, which aremuch larger than the tolerances which are acceptable in for examplelaminate floors connected with tight edges. Such comparatively largetolerances are acceptable since tiles are often produced with bevelededges and installed with a distance filled with grout material.Conventional tiles may also be pressed down into the adhesive compoundmaterial in order to adjust thickness tolerances.

When tiles are installed floating on a foam material thickens toleranceswill be visible. The locking system is preferably formed with the rearside as the reference side. High quality tiles have already sufficientthickness tolerances to allow a high quality installation with amechanical locking system. The thickness tolerance may be improved andthis allows that the space S between tiles may be decreased considerablyto about 1 mm and that tiles may be formed without beveled edges.Further improvement may be obtained if filler layers 34 a, 34 b areapplied on the rear side of the tile as shown in FIG. 12a , preferablyafter the firing in the furnace. One embodiment of the invention is atile comprising a ceramic tile body and a filler 34 a, 34 b at the rearside. The filler is used to reduce thickness tolerances. Thicker tiles 1may have a thinner filler layer 33 a and thinner tiles may have athicker filler layer 34 b. Fillers make it possible to reduce thicknesstolerances from about 1 mm to 0.1-0.2 mm. A part of the filler layer 33may be formed as an equalizing groove 21 that may be used to house aportion of the strip part 7. The filler may comprise thermoplastic ormineral based material that preferably is moisture proof. The filler 34may be used to eliminate thickness tolerance even in tiles without amechanical locking system

The strip part 6 in this embodiment of the invention is preferablyformed as an extruded plastic or metal section that is preferably usedto connect adjacent tile edges with angling and/or horizontal snapping.The strip body 7 comprises a vertically extending tongue body 30 and twohorizontally protruding tongues 10 a and 10 b connected to the tonguebody 30. The tongue body and the protruding tongues may or may not beflexible. One of the protruding tongues 10 b comprises preferably upper42 and lower 43 a contact surfaces that prevent vertical separation andthat are displaced horizontally in relation to each other such that thelower contact surface 43 a is closer to the vertical plane VP than theupper contact surface 42. Such geometry facilitates an easy angling andthe rotation point Rp may be located under the protruding tongue 10 b asshown in FIG. 12c . FIG. 12b shows that a lower contact surface 43 bpreventing vertical separation may also be formed between a lower partof tile and the strip body 7.

FIG. 12d shows that the locking system may be installed with horizontalsnapping. The protruding part of the strip body is bended downwards andthe locking element 8 b snaps into the vertical groove 14 b

FIG. 12e shows that the locking elements 8 a, 8 b may comprise flexiblefixing elements 16 a, 16 b that creates a friction force between thehorizontal grooves 14 a, 14 b and the locking elements 8 a, 8 b andprevent displacement of two adjacent edges 1, 1′ along the edges. Suchlocking system may be formed at two adjacent edges, for example the longedges, and may be used to prevent separation of the other two pair ofedges, for example the sort edges, since the friction between the strippart 6 and the tiles 1. 1′ prevents mutual displacement. The strip partmay of course also be glued to the edge of one of the tiles 1 a.

FIG. 13a shows a tile 1 a made of ceramic material comprising one pairof opposite long edges 4 a, 4 b and one pair of opposite short edges 4c, 4 d. The tile may be a plank shaped panel with a length of forexample 0.8-1.2 m and a width of 0.1-0.2 m. The thickness is preferably8-10 mm. Such ceramic panels with a wood décor may be used to replacefor example laminate floorings with a wood décor in areas where highmoisture resistance is needed. A mechanical locking system isparticularly suitable to connect and install ceramic plank shaped panelsand to form a waterproof floating floor. The installation is preferablymade with offset short edges similar to an installation of wood andlaminate floors. Long edges may be used to obtain high friction forcesand to prevent displacement along the joint. Ceramic material is rigidand in many applications it is not necessary to use a tongue to lock theshort edges vertically since the short edges may be locked verticallywith the connected long edges. The edges may be formed with bevels andthe space between the upper edges may be reduced to about 1 mm or evento a few tenths of a millimeter. The panels may also be installed withcontact between the upper edges. Flexible material may be appliedbetween the edges in order to prevent water to penetrate trough thejoint and the locking system and down to the sub floor.

The plank shaped ceramic panel or tile is preferably digitally printedwith a wood décor. The surface comprises preferably an embossing 29 thatis made in register with the design as shown in FIG. 13d . A tile or aceramic panel may comprise a so-called embossed in register surfacestructure similar to structures formed in laminate floorings. Theembossing is formed by steel plates or structured foils that are pressedagainst the powder material prior to the heating process.

The strip part 6 extends in this embodiment along the whole long edge 4b and an edge portion 6 a extends beyond the short edge 4 d. The panelsaccording to this embodiment have no locking system on the short edges.FIG. 13b shows the rear side. All locking systems used according to thisdisclosure may be used on long and/or short edges.

FIG. 13c shows an installation of several tiles or panels 1 a-1 e. Afirst tile 1 a is installed in a first row R1. A second tile 1 b in asecond row R2 is connected with angling to the first tile 1 a in thefirst row R1. A third tile 1 c is installed with angling against thefirst tile 1 a in the first row R1. The edge portion 6 a of the strippart gives an accurate spacing of the short edges 4 c, 4 d. A fourthtile 1 d is installed and locked to the second 1 b and third tile 1 c inthe second row R2. The locked long edges of the first 1 a and the fourthtile 1 d prevents a separation of the short edges 4 c and 4 d of thesecond 1 b and the third 1 c tiles in the second row R2 and all edgesare locked vertically and horizontally.

FIG. 13d shows a tile 1 a with an underlay 2 attached to the rear side.The undelay covers preferable the major part of the strip and may beused to reinforce the strip part and/or to increase the connectionbetween the strip part and the tile 1 a. The underlay may be a foam,cork material, rubber or similar material and may also be used toincrease the friction between the underlay 2 and the sub floor 3. Theunderlay may also comprise glass fibres or may be an LVT or WPC sheet.

Core grooves 56 may be formed in the rear side of a tile in order todecrease the weight. The strength of the tile may still be sufficientespecially if the core grooves are covered with appropriate underlaymaterials 2 that preferably are bonded to the rear side. Preferably,such underlay material 2 comprises glass fibres that preferably arecombined with a polymer material.

FIG. 13d shows that embossing 29 may be formed with different glosslevels 44 a or 44 b.

Preferably such different gloss levels are combined with an in registerembossed structure. The upper part 44 a of the embossed structure mayhave a lower or higher gloss level than the lower part 44 b. Theadvantage is that the visual embossing will be more pronounced even whenthe lower parts of the embossed portions are only about 0.2-0.5 mm belowthe upper parts and such tiles are easier to clean.

Different gloss levels may be formed with digital printing. A binderpattern may be applied with a digital ink head, powder may be applied onthe pattern and non-bonded powder may be removed.

It is obvious that the above described embodiments comprising anunderlay, embossing with different gloss levels and core grooves may beused individually, in combinations and in conventional tiles without amechanical locking system.

FIGS. 14a-14e show embodiments that preferably may be used to connectshort edges with vertical folding. FIG. 14a shows straight edgeportions. FIGS. 14b and 14c shows edge portions comprising a tongue 10and a recess 45 that are used to obtain a correct space between theedges and to position the edges horizontal such that a new tile may beeasier to connect with angling to the long edges. FIGS. 14d and 14e showa strip part that only locks horizontally.

FIGS. 15 show a flexible tongue 10 that may be used to connect adjacentedges. The tongue comprises flexible protrusions 46 that may be locatedin an inner part of an essentially horizontal groove or at an outer partof the tongue and that may protrude beyond a vertical plane. FIGS. 15a,15c, 15e shows the flexible tongue in an outer position and FIGS. 15b,15d shows the tongue in an inner position during folding.

It is an advantage to use a tongue comprising flexible protrusionsprotruding beyond the vertical plane when tiles are locked with a spaceS between upper edges. The tongue may be firmly fixed into the grove 9since there are no parts that have to be displaced in the inner part ofthe groove 9 during locking. The tile edges are rigid and sufficientlocking strength may be obtained even in the case when the protrudingprotrusions are spaced from each other.

FIGS. 16a shows an embodiment comprising a strip part 6 having avertically protruding tongue body 30 comprising a horizontally extendingtongue 10 a′ at an upper part connected to a first horizontal groove 9a′. A flexible tongue 10 a with flexible protrusions 46 in located in aninner part of the horizontal groove 9 a is connected into a secondhorizontal groove 9 a located at the same edge and above the firsthorizontal groove 9 a′. The adjacent edge 1′ comprises an essentiallyrigid tongue 10 b located in a horizontal groove 9 b. The flexibletongue 10 a comprises a sliding surface 33 a at its upper an outer partthat cooperates during locking with a sliding surface 33 b located onthe lower and outer part of the adjacent rigid tongue 10 b.

FIG. 16b shows the edges 1, 1′ in locked position. The tongue body 30 ispreferably used to prevent displacement of the edges towards each other.

FIG. 16c shows an embodiment where a rigid tongue 10 a and the strippart 6 are located and connected to the same edge 1. The flexible tongue10 b is located in the adjacent edge 1′. The rigid tongue 10 a comprisesa sliding surface 33 a in its upper and outer part and the flexibletongue 10 b comprises a sliding surface 33 b at its lower and outerpart.

The separate tongues and the strip part 6 may be used separately or incombination. A strip part 6 that only connect the edges horizontally maypreferably be attached to the lower part of the edges a shown in FIG.16a . The long edges may for example be locked with a locking system asdescribed in FIG. 12d . The strip part combined with the separatetongues may be used to connect for example the long edges or the shortedges with angling or horizontal snapping.

FIG. 16d shows a method to connect the strip part 6 to the first edge 1.The strip part 6 is moved essentially horizontally towards the edge andconnected to the first horizontal groove 9 a. The locking element 8 a ispressed into the first vertical groove 14 a. Preferably a pressing wheel49 is used. FIG. 16e shows that the strip part may be glued to the firstedge 1. A glue layer 57 a, 57 b may be applied between the strip body 7and a lower part of the tile and/or between a vertical edge part and thetongue body 30. A sublayer 2 may be bonded or glued with a glue layer 57d to a rear side of the tile 1 and the strip part 6 may also be gluedwith a glue layer 57 c to the sub layer 2. This embodiment ischaracterized in that a vertical 14 b and a horizontal 9 b groove isonly formed in one 1′ of two opposite edges 1, 1′. One of the edgescomprises preferably an end edge 1 that is essentially vertical from thetile surface and to the rear side of the tile. Gluing of the strip partto a tile may be combined with all other embodiment described in thisdisclosure.

FIGS. 17 shows a locking system comprising a flexible tongue 10 a havingflexible protrusions 46 that protrude beyond the vertical plane VP asshown in FIG. 15c . The strip part 6 is similar to the strip part 6shown in FIG. 16a . The flexible protrusions comprises a sliding surface33 a at the upper and outer part that during vertical displacementcooperates with a sliding surface 336 b formed at the lower part of anadjacent tile edge 1′. The flexible protrusions 46 are essentiallydisplace horizontally within the space S between the edges. The lockingelement 8 b and a locking groove 14 b prevents a horizontal displacementinwardly and outwardly. Such displacement may also be prevented withhorizontally protruding parts 30′ located between the edges.

FIGS. 17d and 17e show that all embodiments of the disclosure may beused to connect tiles 1 a, 1 b to an indoor or outdoor wall 58.Preferably the strip part is mechanically connected with spikes, screws,special clips or extrude profiles and similar. Tiles may also be gluedto a wall and the strip part 6 may be used to position the tiles.

FIGS. 18a-c show a strip part comprising a tong body 30 having a tongue10 a and a tongue groove 9 b. The adjacent edge comprises preferably aflexible tongue 10 b located in a horizontal groove 9 c. FIG. 18d showsthat the tile edges may be designed such that they are possible to bereleased after installation. The grout material is removed and adisassembly tool 55 is inserted via the space S and into the grove 9 bsuch that a flexible tongue is pressed inwardly towards the tile edgeand the locking system released. All embodiments of the inventioncomprising a flexible tongue may be disassembled in a similar way.Locking systems with flexible tongues allow that tiles may bedisassembled in a middle section of a floor. Tiles may also bedisassembled from the first and the last rows.

FIGS. 19a-19c shows essentially the same embodiment as in FIG. 18a -c.The flexible tongue 10 b comprises a flexible snap tab 47 at its outerend. The flexible tongue 10 b may be connected to the folding tile 1′ asshown in FIG. 19a or to the strip tile 1 comprising the protruding strippart 6 as shown in FIG. 19 d.

FIGS. 20a-c show a strip part 6 comprising a tong body 30 having atongue 10 a and a tongue groove 9 a′ formed in the tongue body 30. Theadjacent edge 1′ comprises preferably an essentially rigid tongue 10 blocated in a horizontal groove 9 b. FIG. 20d shows that a rigid tongue10 b may also be formed in the tile material. The horizontal groove 9 a′may be formed close to the adjacent edge 1′ and the rigid tongue 10 bmay be rather small and may protrude about 1-2 mm beyond the upper edgeeven in the case when the tiles are installed with a space of 2-5 mmbetween the upper edges. FIG. 20c shows that a flexible grout material13 may be bonded to the upper part of the tongue body 30. FIG. 20d showsthat the grout material 13 may be mechanically connected to the tonguebody 30.

FIG. 21 shows that tiles are not completely rectangular or square.Length L or width W may vary. Long and short edges 4 a, 4 b, 4 c, 4 dare often not completely parallel with each other and long edges areoften not completely perpendicular and formed with a perfect 90 degreeangle.

Theoretically tiles may be machined such that size tolerances areeliminated. Practically this is not a suitable method due to high costsand the fact that bevels or rounded edges will be damaged. Horizontal 9and vertical 14 grooves cannot be formed with the upper edges as areference surface since tolerance will be accumulated and larger areascomprising several tiles installed in several rows will not be possibleto install.

The locking system must be designed such that each row is perfectlyaligned and that the size tolerances of the tiles are compensated byvariations of the space S between the edges. This is a major differencecompared to laminate and wood floors that are machined to a perfectrectangular form and installed with a tight fit between the upper edges.

The problem may be solved with a positioning system that prior to theforming of the grooves align the tiles with a predetermined position ofone long edge 4 a and one short edge 4 c. Such alignment may be madewith cameras or with a positioning tool 50 as shown in FIG. 21. Thepositioning tool comprises a first positioning surface 51 and a secondpositioning surface 52 that are completely perpendicular to each other.A long edge 4 a or a first edge in case the tiles are square, isdisplaced such that it is in contact with the first positioning surface51. The tile is thereafter displaced along the positioning surface untila short 4 c or a second edge is in contact with the second positioningsurface 52. FIG. 21 shows a tile with a contact point 53 at an outertile corner.

After positioning of the tile vertical and horizontal grooves are formedparallel with the first and second positioning surfaces and with apre-defined distances D1, D2, D3, D4, D5, D6, D7. One of the edges,preferably one of the long edges 4 a that has been positioned againstthe first positioning surface 51 comprises grooves 14 a, 9 a that areessentially parallel with the edge. At least one of the other edges maycomprise horizontal or vertical grooves with an actual horizontaldistance Ad3, Ad4 to the edge that varies along the edge, in case theedge is not parallel with a pre-defined geometry. Such distance may varybetween the same edge of two different tiles, for example to thevertical groove 14 a that is used to connect the strip part or to theadjacent vertical groove 14 b that during locking is connected to thestrip parts as shown in FIG. 20a in case the length L or width Wdeviates from a pre-determined geometry.

FIG. 21b shows a cross section A-A at one part of a short edges 4 c andFIG. 21c shows a cross section B-B at another part of the short edge 4c. The edge is not completely parallel with the positioning tool. Thehorizontal groove 9 and the vertical groove 14 c are formed at apre-defined distances D2, D3 from an aligned position defined by thepositioning tool 50. The actual horizontal distances Ad3, Ad4, Ad5, Ad6from the vertical plane VP and to the inner wall 20 of the horizontalgroove 9 and to the first wall 24 of the vertical groove 14 c variesalong the edge 1. The figures show that even the lower lip 11 may beformed against a pre-determined position. This means that the actualhorizontal distance Ad7, Ad8 between the outer part of the lower lip 11and the upper edge or the vertical plane VP may vary along the edge.

FIGS. 21d and 21e show that the above described distances Ad7, Ad8 on anedge 4 b of a first tile and the distances Ad7′, Ad8′ and on an edge 4b′ of a second tile may vary between the same groves parts 24, 24′, 20,20′ located on the same edge 4 b, 4 b′ of two different tiles 1 a and 1b when the tiles 1 a, 1 b have different widths or lengths.

Preferably the tiles according to the invention are characterized inthat there is a first horizontal distance Ad7 between a first groovewall 24 of a first edge 1 of a first tile 1 a and an upper and outerpart of the first edge 1 of the first tile 1 a,

that there is a second horizontal distance Ad9 between a first groovewall 24 of a second edge 1′ of a first tile 1 a and an upper and outerpart of the second edge 1′ of the first tile 1 a,

that there is a third horizontal distance Ad7′ between a first groovewall 24 of a first edge 1 of a second tile 1 b and an upper and outerpart of a first edge 1 of the second tile 1 a,

that there is a fourth horizontal distance between a first groove wall24 of a second edge 1′ of the second tile 1 b and an upper and outerpart of the second edge 1′ of the second tile 1 b.

The first horizontal distance may vary along the first edge 1 of thefirst tile 1 a and/or the second horizontal distance may vary along thesecond edge 1′ of the second 1 b tile. The third horizontal distance mayvary along the first edge 1 of the second tile 1 b. The fourthhorizontal distance may vary along the second edge 1′ of the second tile1 b. The first horizontal distance may be different from thirdhorizontal distance and/or the second horizontal distance may bedifferent from the fourth horizontal distance.

The above-described method may be used to form floor panels as describesin FIG. 9c . The horizontal distance from the vertical plane VP and tothe outer part of the tongue 10, and/or the inner part of the tonguegroove 9, and/or to the a surface on the locking element 8, and or to assurface on the locking groove 14 may vary along at least one of theedges of the panel or between two opposite edges.

It is a major advantage if flexible grout material may be integratedwith a tile edge and factory connected prior to installation. The groutmaterial serves several purposes. It is used to compensate sizetolerances, to prevent water to penetrate into the joint and to createdecorative effects. Grout material may be attached to all four edges oronly on one long and one short edge. The disadvantage is that aninstallation will comprise many joints between the grout materials.

FIG. 22a shows that a preferably flexible grout material 13 a may beattached to only one edge of a tile, preferably a short edges 4 d if thetiles are rectangular. Two rows R1, R2 of tiles 1 a-1 i may be installedas shown in FIG. 22a . A continuous grout material 13 b, preferablyformed as a flexible strip, may be inserted and pressed in between twoinstalled rows R1, R2 as shown in FIG. 22b . The advantage is that acorner section will only comprise two joints 54 a, 54 b or only onejoint 54 b in case the tiles are installed with offset short edges 1 f,1 j as shown in FIG. 22b . The Grout materials may be pressed againsteach other in the joints with a permanent pre tension and an almostinvisible and moisture resistant joint may be formed.

FIG. 23a shows an embodiment comprising upper 9 a′, 9 b′ and lower 9 a,9 b horizontal grooves formed in the edge. The upper grooves 9 a′, 9 b′may be used to accommodate a part of the grout material 13 and they maybe formed such that they prevent vertical displacement of the edges whena grout material is applied between the edges. In some embodiments itmay be possible to exclude the lower horizontal grooves 10 a, 10 b andthe strip part may be connected to the edge with vertically extendingtongue parts 10 a, 10 b that are locked to the vertical part of edgewith friction forces. The strip part 6 may be used mainly to lock theedges in the horizontal direction and grout material may be used to lockthe edges vertically. The locking system may be locked with angling,horizontal snapping and vertical snapping. The vertical grooves 14 a, 14b and the locking elements 8 a, 8 b are preferably formed withcooperating locking surfaces extending vertically upwards with a lockingangle A of about 90 degrees against a horizontal plane H. The advantageis that a strong horizontal locking may be achieved and may be combinedwith an easy locking and connection of the strip part. This may beaccomplished with vertically extending tongue bodies 30 a, 30 b that maybe flexible and may be bended in the space S when the strip part 6 isconnected to the first edge 1 and during locking.

FIG. 23b shows a strip part 6 comprising tongues 10 a, 10 b and lockingelements 8 a, 8 b formed by punching of a metal sheet, preferably asheet of stainless steel with a thickness of preferably 0.3-0.5 mm. Thecavity 59 a, which is needed to form the first tongue 10 a, is locatedbetween the first locking element 8 a and the first tongue 10 a. Thecavity 59 b, which is needed to form the second tongue 10 b, is locatedbetween the second tongue and the second locking element 8 b.

Such an embodiment provides increase flexibility especially if the tiles1 a, 1 b are connected with horizontal snapping as shown in FIGS. 23cand 23d . The tongue 10 b is during snapping pushed towards the adjacentedge horizontally and the tongue locking surface 32 is displacedslightly vertically upwards such that an easy locking may be obtainedwhen the strip part 7 is bended backwards.

The locking system may be configured such that the horizontal lockingforce that prevents the edges to separate away from each other isstronger than the locking force that prevents the edges to be displacedtowards each other. Displacement of the edges towards each other may beprevented by grout material applied in the space S.

FIGS. 24a, 24b show installation of tiles with a snapping action thatconnect both a first 4 a and a second 4 b edge of a tile 1 d with anessentially diagonal displacement towards two adjacent tiles 1 b, 1 c.Preferably a first 4 a and a second edge 4 c of a first tile 1 d isplaced on adjacent strip parts 6 c, 6 d, 6 e, 6 f of a second 1 b andthird 1 c tile and the first tile 1 d displaced essentially horizontallytowards the second and third tiles such that a snapping connection isobtained. The advantage is that it is not necessary to connect forexample a first edge 4 a of a tile 1 d to an adjacent tile 1 c withhorizontal snapping and then displace the tile 1 d in locked conditionand with high friction forces along the long edge 4 a in order to snapthe short edge 4 c to another tile 1 b.

All embodiments of the invention may be combined and used incombinations on different edges but also on the same edge. FIG. 24ashows that for example an edge 4 a, 4 b of a tile 1 d may compriseseveral different separate materials 10 a and strip parts 6 a connectedto vertical and/or horizontal grooves. The strength of the verticallocking may be increase if for example a separate tongue 10 a isattached in a horizontal groove. Such separate tongue 10 a may be forexample located between two strip parts 6 a, 6 b. The tongue 10 a may berigid or flexible and may be used to connect tiles with angling,vertical snapping and horizontal snapping.

A separate tongue 10 a located between two strip parts 6 may for examplebe used to replace the second tongue 10 b in FIG. 23c and snapping maybe obtained by just a bending of the protruding strip body 7. It isobvious that the separate tongue 10 a may be connected to horizontalgrooves formed in the first 1 and/or the second 1′ edge and that severalseparate tongues may be attached to both edges, preferably offset toeach other in the length direction of the joint edges.

FIG. 24b shows that an underlay 2 may be factory connected to the rearside of the tile 1 d and under the strip parts 6 a, 6 b. The underlaymaterial may comprise flexible material that increase the frictionbetween the underlay and the sub floor and may be combined with anelectrical floor heating system.

FIGS. 25a and 25b show a strip part 6 that may be used as a corner partto lock eight adjacent edges of four tiles 1 a, 1 b, 1 c, 1 d. The strippart 6 comprises locking elements 8 a, 8 a′ and tongues 10 a, 10 a′configured to be locked to a first edge 4 b and a second edge 4 d whichare perpendicular and adjacent to each other and form a part of a cornersection of a tile. Such strip parts 6 configured to be used as cornerparts 6 are particularly suitable to connect tiles, which are installedvertically on a wall, and only one screw may be needed to connect acorner part 6 to a wall.

All horizontal and vertical grooves and all equalizing grooves mayextend along the whole edge or may be formed on only a part of an edgepreferable where the strip parts 6 are intended to be connected to anedge. Preferably rotating tools with jumping tool heads may be used toform grooves in a part of an edge.

EMBODIMENTS

1. A set of ceramic or stone tiles comprising a first tile (1 a)provided with a first edge (1) and a second tile (1 b) provided with asecond edge (1′) wherein the tiles are provided with a locking systemfor locking the first edge (1) to the second edge (1′) in a horizontaldirection parallel with a tile surface and in a vertical directionperpendicular to the horizontal direction, said locking system comprisesa first and a second tongue (10 a, 10 b) and a strip part (6) providedwith a first and a second locking element (8 a, 8 b), characterized in:

that the first edge (1) is provided with a first horizontal groove (9 a)and a first vertical groove (14 a) formed in a body of the first tile (1a), wherein the first locking element (8 a) is configured to cooperatewith the first vertical groove (14 a) for locking in the horizontaldirection and the first tongue (10 a) is configured to cooperate withthe first horizontal groove (9 a) for locking in the vertical direction,that the second edge (1′) is provided with a second horizontal groove (9a) and a second vertical groove (14 b) formed in a body of the second (1b) tile wherein the second locking element (8 b) is configured tocooperate with the second vertical groove (14 b) for locking in thehorizontal direction and the second tongue (10 b) is configured tocooperate with the second horizontal groove (9 b) for locking in thevertical direction, that each of the first and the second horizontalgroove (9 a, 9 b) comprises an upper lip (12) and a lower lip (11),

that the lower lip (11) of the first horizontal groove (9 a) extendshorizontally to or is within an upper and outer part of the first edge(1) and the lower lip (11) of the second horizontal groove (9 b) extendshorizontally to or is within an upper and outer part of the second edge(1′),

that there is a space (S) between the outer and upper part of the firstedge (1) and the outer and upper part of the second edge (1′) in alocked position of the first and the second edge (1, 1′).

2. The set of embodiment 1 characterized in that the lower lip (11) ofthe first horizontal groove (9 a) extends horizontally essentially tothe upper and outer part of the first edge (1) and the lower lip (11) ofthe second horizontal groove (9 b) extends horizontally essentially tothe upper and outer part of the second edge (1′).

3. The set of embodiment 1 or 2, wherein a depth of the first horizontalgroove (9 a) measured as the horizontal distance from a vertical plane(VP), located at the upper and outer part of the first edge, and to abottom of the first horizontal groove, varies along the first edge; or

wherein a depth of the second horizontal groove (9 b), measured as thehorizontal distance from a vertical plane (VP), located at the upper andouter part of the second edge, and to a bottom of the second horizontalgroove (9 b), varies along the second edge.

4. The set of embodiment 3, wherein the depth of the horizontal groovevaries with at least 0.10 mm.

5. The set of any one of the preceding embodiments 1-4, wherein thestrip part (6) comprises a vertically extending tongue body (30),wherein the first tongue (10 a) protrudes from the vertically extendingtongue body (30).

6. The set of any one of the preceding embodiments 1-5, wherein thelocking system is configured to be locked by angling and/or verticalsnapping and/or horizontal snapping of the first (1) and the second tile(1′).

7. A set of ceramic or stone tiles (1 a, 1 b), each comprising a first(1) and a second (1′) edge which are provided with a locking system forlocking in a horizontal direction parallel with a tile surface and in avertical direction perpendicular to the horizontal direction, whereinthe first edge (1) of the first tile (1 a) is lockable in the verticaland in the horizontal direction to the second edge (1′) of the secondtile (1 b), wherein the second edge (1′) of the first tile (1 a) islockable in the vertical and in the horizontal direction to the firstedge (1) of the second tile (1 b), wherein said locking system comprisesa first and a second tongue (10 a, 10 b) and a strip part (6) providedwith a first and a second locking element (8 a, 8 b), characterized in:that the first edge (1) is provided with a first horizontal groove (9 a)and a first vertical groove (14 a) formed in a body of the first and thesecond tile (1 a, 1 b), respectively, that the second edge (1′) isprovided with a second horizontal groove (9 a) and a second a verticalgroove (14 b) formed in a body of the first and the second tile (1 a, 1b), respectively,

wherein the first locking element (8 a) is configured to cooperate withthe first vertical groove (14 a) for locking in the horizontal directionand the first tongue (10 a) is configured to cooperate with the firsthorizontal groove (9 a) for locking in the vertical direction,

wherein the second locking element (8 b) is configured to cooperate withthe second vertical groove (14 b) for locking in the horizontaldirection and the second tongue (10 b) is configured to cooperate withthe second horizontal groove (9 b) for locking in the verticaldirection,

that each of the first and the second vertical groove (14 a, 14 b)comprises a first groove wall (24), a second groove wall (25) and anupper surface (25), that the first groove wall (24) of the firstvertical groove (14 a) is closer to the upper and outer part of thefirst edge (1) than the second groove wall (25) of the first verticalgroove (14 a)

that the first groove wall (24) of the second vertical groove (14 b) iscloser to an upper and outer part of the second edge (1′), than thesecond groove wall (25) of the second vertical groove (14 b),

that there is a first a horizontal distance (Ad7) between the firstgroove wall (24) of the first edge (1) of the first tile (1 a) and anupper and outer part of the first edge (1) of the first tile (1 a),

that there is a second horizontal distance (Ad9) between the firstgroove wall (24) of the second edge (1′) of the first tile (1 a) and anupper and outer part of the second edge (1′) of the first tile (1 a),

that there is a third horizontal distance (Ad7′) between the firstgroove wall (24) of the first edge (1) of the second tile (1 b) and anupper and outer part of the first edge (1) of the second tile (1 a),

that there is a fourth horizontal distance between the first groove wall(24) of the second edge (1′) of the second tile (1 b) and an upper andouter part of the second edge (1′) of the second tile (1 b),

that the first horizontal distance varies along the first edge (1) ofthe first tile (1 a); and/or the second horizontal distance varies alongthe second edge (1′) of the second (1 b) tile;

and/or the third horizontal distance varies along the first edge (1) ofthe second tile (1 b);

and/or the fourth horizontal distance varies along the second edge (1′)of the second tile (1 b);

and/or the first horizontal distance is different from third horizontaldistance and/or the second horizontal distance is different from thefourth horizontal distance.

8. The set of embodiment 7, wherein in a locked position of the first(1) and the second edge (1) there is a space (S) between the upper andouter parts of the first and second edge.

9. The set of embodiment 7 or 8, wherein each of the first and thesecond horizontal groove (9 a, 9 b) comprises an upper lip (12) and alower lip (11), that the lower lip (11) of the first horizontal groove(9 a) extends horizontally to or is within an upper and outer part ofthe first edge (1) and the lower lip (11) of the second horizontalgroove (9 b) extends horizontally to or is within an upper and outerpart of the second edge (1′). 10.The set of embodiments 7-9, wherein thestrip part (6) comprises a vertically extending tongue body (30),wherein the first tongue (10 a) protrudes from the vertically extendingtongue body (30).

11. The set of any one of the preceding embodiments 7-10, wherein thelocking system is configured to be locked by angling and/or verticalsnapping of the first and the second tile (1 a, 1 b).

12. Ceramic tiles (1 a, 1 b) provided with an embossed surface and adécor, characterized in that the embossing is in register with thedécor, that the embossing comprises upper (44 a) and lower (44 b)surface portions wherein an upper surface portion (44 a) comprises adifferent gloss level than a lower surface portion (44 b).

13. Ceramic tiles of embodiment 12, wherein the décor is a wood designand wherein the different gloss levels are formed by a digitally appliedpowder.

14. A set of floor panels comprising a first (1 a) and a second (1 b)panel comprising a ceramic surface layer (27) and a core (28) comprisingthermoplastic material mixed with

wood or mineral fillers, characterized in: that a mechanical lockingsystem is formed in the core (28) of the first (1 a) and the secondpanel (1 b),

that the mechanical locking system comprises a strip (7) provided with alocking element (8) at a first edge (1) of the first panel (1 a) and alocking groove (14) at a second edge (1′) of the second panel (1 b),wherein the locking element (8) and the locking groove (14) areconfigured to cooperate for locking of the first (1) and the second edge(1′) in a horizontal direction parallel with the ceramic surface layer(27), that the mechanical locking system comprises a tongue (10) at thesecond edge (1′) and a tongue groove (9) formed in the first (1) edge,wherein the tongue (10) and the tongue groove (9) are configured tocooperate for locking of the first and the second edge (1,1′) in avertical direction perpendicular to the horizontal direction, that thethickness of the ceramic surface layer is in the range of 2 mm to 5 mm,and that the tongue groove (9) comprises an upper lip (12) that isessentially formed by the ceramic surface layer (27).

15. The set of embodiment 14, wherein in a locked position of the first(and the second edge (1,1′) there is a space S of about 1-10 mm betweenthe ceramic surface layers.

16. A pre formed ceramic tile (1) intended to be provide with a lockingsystem characterized in that a groove (21, 14) is formed at the rearside of a tile edge (1). 17. A pre formed ceramic tile (1 a) tile ofembodiment 16, wherein a first thickness (T′) of an outer edge of thepre formed ceramic tile is lower than a second average thickness (T) ofthe tile body of the pre formed ceramic tile.

18. A pre formed ceramic tile (1 a) of embodiment 17, wherein thethickness difference between the first thickness (T′) and the secondaverage thickness (T) is about 1-3 mm.

19. A pre formed ceramic tile (1,1′) of any one of the embodiments16-18, wherein the groove is an equalizing groove (21) comprising anupper surface (21 a) that is essentially parallel with an upper surfaceof the pre formed ceramic tile (1 a), wherein the upper surface extendsfrom the outer part of the edge and inwardly.

20. A pre formed ceramic tiles (1 a) of embodiment 17-19, wherein theupper surface (21 a) of the equalizing groove extends over a horizontaldistance of about 3-20 mm.

21. A pre formed ceramic tiles (1,1′) of embodiment 17-20, wherein therear side of the pre formed ceramic tile edge (1) comprises a verticalgroove (14) spaced from the outer edge and an equalizing groove (21)extending from the vertical groove (14) and to the outer part of theedge.

22. A set comprising a first tile (1 a), a second tile (1 b) and a strippart (6), which preferably comprises a polymer or metal material,wherein said first and second tile (1 a, 1 b) are ceramic or stonetiles, characterized in

that a first edge (1) of the first tile (1 a) or a second edge (1′) ofthe second tile (4 b) comprises a vertical groove (14 a, 14 b) and ahorizontal groove (9 a, 9 b) formed in a body of the first or the secondtile (1 a, 1 b), respectively,

that said strip part (6) is configured to be connected to one of thevertical grooves (14 a, 14 b) and one of the horizontal groove (9 a, 9b), formed on the same edge, for vertical locking perpendicular to thetile surface and horizontal locking parallel to the tile surface of thefirst and the second tiles (1 a, 1 b), and

that in locked position there is a space S between upper parts of thefirst and second edge (1,1′).

23 The set of embodiment 22, wherein vertical (14 a, 14 b) andhorizontal (9 a, 9 b) grooves are formed in the first edge (1) of thefirst tile (1 a) and the second edge (1′) of the second tile (4 b) andwherein the strip part is configured to be connected to the horizontal(9 a, 9 b) and vertical (14 a, 14 b) groves formed in the first (1) edgeof the first tile (1 a) and in the second (1′) edge of the second tile(1 b).

24. The set of embodiment 22 or 23, wherein the horizontal groove (9 a,9 b) of the first edge (1) or the second edge (1′) comprises an upperlip (12) and a lower lip (11), and wherein the lower lip (11) extendshorizontally to or is within an upper and outer part of the respectivefirst (1) or second (1′) edge.

25. The set of any one of the embodiments 22-24, wherein the strip part(6) comprises a tongue (10 a) having a vertically extending tongue body(30) located in the space (S).

26. The set of embodiment 25, wherein the tiles may be connected withvertical or horizontal snapping and wherein the tongue body (30) isdisplaced horizontally in the space (S) during locking.

1. (canceled)
 2. A set of ceramic or stone tiles comprising a first tileprovided with a first edge and a second tile provided with a secondedge, wherein the tiles are provided with a locking system for lockingthe first edge to the second edge in a horizontal direction parallelwith a tile surface and in a vertical direction perpendicular to thehorizontal direction, the locking system comprising a first tongue and asecond tongue and a strip part provided with a first locking element anda second locking element, wherein: the first edge is provided with afirst horizontal groove and a first vertical groove formed in a body ofthe first tile, wherein the first locking element is configured tocooperate with the first vertical groove for locking in the horizontaldirection and the first tongue is configured to cooperate with the firsthorizontal groove for locking in the vertical direction, the second edgeis provided with a second horizontal groove and a second vertical grooveformed in a body of the second tile, wherein the second locking elementis configured to cooperate with the second vertical groove for lockingin the horizontal direction and the second tongue is configured tocooperate with the second horizontal groove for locking in the verticaldirection, each of the first horizontal groove and the second horizontalgroove comprises an upper lip and a lower lip, and there is a spacebetween the outer and upper part of the first edge and the outer andupper part of the second edge in a locked position of the first edge andthe second edge.
 3. The set as claimed in claim 2, wherein the lower lipof the first horizontal groove extends horizontally to or is within anupper and outer part of the first edge and the lower lip of the secondhorizontal groove extends horizontally to or is within an upper andouter part of the second edge.
 4. The set as claimed in claim 2, whereinthe lower lip of the first horizontal groove extends horizontallyessentially to the upper and outer part of the first edge and the lowerlip of the second horizontal groove extends horizontally essentially tothe upper and outer part of the second edge.
 5. The set as claimed inclaim 2, wherein the lower lip of the first horizontal groove extendshorizontally beyond an upper and outer part of the first edge and thelower lip of the second horizontal groove extends horizontally beyond anupper and outer part of the second edge.
 6. The set as claimed in claim2, wherein a depth of the first horizontal groove measured as thehorizontal distance from a vertical plane, located at the upper andouter part of the first edge, and to a bottom of the first horizontalgroove, varies along the first edge; or wherein a depth of the secondhorizontal groove, measured as the horizontal distance from a verticalplane, located at the upper and outer part of the second edge, and to abottom of the second horizontal groove, varies along the second edge. 7.The set as claimed in claim 6, wherein the depth varies with at least0.10 mm.
 8. The set as claimed in claim 2, wherein the strip partcomprises a vertically extending tongue body, and wherein the firsttongue protrudes from the vertically extending tongue body.
 9. The setas claimed in claim 2, wherein the locking system is configured to belocked by angling and/or vertical snapping and/or horizontal snapping ofthe first tile and the second tile.
 10. The set as claimed in claim 2,wherein the ceramic or stone tiles are floor panels with hard surfacesbonded to a sheet shaped material.
 11. The set as claimed in claim 2,wherein a flexible grout material formed as a flexible strip is insertedbetween the upper part of the first edge and the upper part of thesecond edge.
 12. The set as claimed in claim 11, wherein the flexiblegrout material is continuous.
 13. The set as claimed in claim 11,wherein the strip part comprises a vertically extending tongue body andwherein the flexible grout material is bonded to an upper part of thetongue body.
 14. The set as claimed in claim 11, wherein the strip partcomprises a vertically extending tongue body and wherein the flexiblegrout material is mechanically connected to the tongue body.
 15. The setas claimed in claim 2, wherein a flexible material is provided betweenthe first edge and the second edge.
 16. The set as claimed in claim 15,wherein the flexible material is provided at least partly in the firsthorizontal groove and the second horizontal groove.